Wrong propellers? Affect fuel consumption? Ferretti 430 sea trial..

[hkikis]

Hello! Today was sea trial of the Ferretti 430!
TAMD 74P
Volvo say 2600rpm rev limit.

2200rpm cruise 23.5knot 150l/h (volvo display)
This was very good and I was happy.

At WOT 2430rpm!!!!
The hull cleaned very good!
I ask him why that? He told me that 10 years is like this the boat!

Nothing bad with smoke to think about fuel pumps and injectors. The engine works very good and the turbo also look to spool nice. 205kpa the display show!

So what else? Wrong propellers! They are too long the propellers for this boat.
If I will fix the propellers to have 150rpm more what will be with the fuel consumption?
At 2200 I will loose some speed theoretically! Also I think that the fuel rate (150l/h) will not decrease !
So in theory I will have worse fuel consumption?

 

[hkikis]

Maybe I am wrong.
If we was at WOT it will be right that the fuel consumption would be the same.
But as we are in partial throttle range (2200rpm) the fuel rate isn't exactly for example if the boat was 12tn and 17tn.
With shorter propeller will have less load... It is like to have lighter the boat.
Right?

So at 2200rpm when I will change propeller I will see less knot but also less l/h ?
Finally do you think that after this change the boat will have better fuel consumption?

Do you think that maybe will be something else? You could buy a boat that cannot reach the rpm of the manufacturer ?

 

[Portofino]

Loadsa questions . Feel you are getting obsessed by the fuel burn

The L/ hr at a set rpm does indeed change with the load .
The load is related to drag , stuff like additional weight eg fully laden , but very much so with seasonal fouling and very slightly with the wave height and strong only wind direction .

A undersized will reduce it and that will pan out in a lower speed @ any given rpm ...An oversized prop will increase it up to the point the engines busting itself from 2430 in your case to reach it rated 2600

You say the hull is clean , but are silent on the stern gear .
Even 2-3 weeks after a lift out and sterngear clean , then it’s parked up on its berth perhaps with the sun beaming under the stern , there will be a surface growth .
In my experience it does spin off within a few hrs .....but you can’t just leave the marina and pick up @ the same rpm where you left off last time you used the boat .
It’s only with access to“ load “ and EGTs along with L/hr you see this relationship.
I normally dive in every trip and give the stern gear a scrape ....even after only a few weeks .

Yes it should reach WOT assuming it’s all clean under the water .
Golden rule when buying is it should reach WOT as per manufacturers or boat test from a mag when new .
Presume you have got hold of previous boat mag test data .......I find theses very accurate ( inc prop dimensions as well ) , on the ITAMA owners group my 2003 engines exactly match the manufactures figures done ...17 years ago ! And did so on it’s sea trail .
I asked if I could WOT it first and held there for 15 mins watching all the gauges ...
It passed .
They say the engines should go a few 3- 4 % over rated rpm ( with everything fresh / clean ) .....and yes I do see that after it’s annual .

You just have the L/hr @ 2200 ....150 .....So 5 Hp per L = 375 / 480 = 78 %

Did you see the fuel burn at the WOT ....your 2430 ? ......should be about 190 L/hr ish ?
I,am not familiar with the 480 p s level of electrotwackerey . In the protective sense ?....one for Volvo Paul to chime in .

What speed did it go at this 2430 rpm

It needs to be able to reach 2600+ rpm ideally 2700 momentarily.

 

[Portofino]

Racking by brains diesels loose out a lot power wise if the valve timing is out or fuel timing .
So we know it’s making roughly 375 Hp per side @2200 rpm , but perhaps because of the above , one or both it cant really reach up to its full 480 ?
eg if the valves are not adjusted , the exhaust gap is large it’s not fully evacuated before the next stroke .
Saying this unfamiliar with the valve timing arrangements of it ? Just poking @ answers if the props are OEM spec , and were cleaned .

 

[kashurst]

walk away from the boat - that is a big discrepancy for a clean hull. You won't get smoke from more modern diesel engine (74Ps have smoke limiters) if it's overloaded either. So no smoke does not mean everything is OK.
don't buy this thinking you can just "sort" the propellors - thats what the manufacturer did and it's not simple and it's an expensive process. So they have either been replaced incorrectly or something else is amiss. Two new propellors @ 5000 euros plus lift, hard standing and mechanics time. It could be as simple as a fuel restriction. If so an easy problem to solve so why has it been ignored for ten years and what else has the owner ignored?
So what if the owner says its been fine for 10 years - its irrelevant. A major part of the boat does not work correctly.
let someone else fix it properly (errr the owner).

re fuel consumption - a boat this big will be doing about 0.6 - 0,7 miles per gallon in good condition, (@ 150 l/hour). No amount of fiddling with the props or engine revs will materially change this - it's physics, 17,500Kgs at @22 Knots through water takes a lot of energy.

 

[Deleted User YDKXO]

Hello! Today was sea trial of the Ferretti 430!
TAMD 74P
Volvo say 2600rpm rev limit.

2200rpm cruise 23.5knot 150l/h (volvo display)
This was very good and I was happy.

At WOT 2430rpm!!!!
The hull cleaned very good!
I ask him why that? He told me that 10 years is like this the boat!

Nope, do not accept that. That is far too large a discrepancy

Who said the hull was clean? Do you know that 100% for sure? And this is the important question. Do you know for sure that the props and sterngear were clean?

If you are absolutely certain that the hull and props were clean before the seatrial then do not go through with this purchase until you get a satisfactory explanation as to why the engines are not pulling 2600rpm

Possible reasons could be incorrectly adjusted throttle mechanism, incorrect RPM indicators, fuel injector issues, fuel pump issues or possibly excess weight on the boat and many other things. But it is up to the seller to tell you why and then put it right

 

[MapisM]

A few questions:

Firstly, did you involve a VP mechanic? There's plenty of other numbers to be consider, in a half decent sea trial.
And only on the basis of all of them, he's the one who should have told you something meaningful about those engines.
Missing that, anything else is neither here nor there, including suggestions that we might try to give you.

Anyhow, having said this, just to try to spot any possible simple explanation that we can't now think of:
What speed did the boat reach at 2430 WOT?
Did you check the fuel burn also at WOT?
Were trim tabs fully raised?
How loaded was she?

 

[Bandit]

Work from first principles:

Most manufacturers figures are based on no gear or stores on board, a spotless hull and stern gear, half fuel and water and two crew and probably a following wind .

Boats get heavier with time, dinghies, spare parts, bedding, food,drink, life rafts, clothes, water, sewage, etc etc etc . my 48 ft boat I reckon has 500kg more gear on than when I bought it.

Measure boat speed accurately over up tide and down tide directions.

Make sure you are measuring fuel consumption accurately.

It does sound like your boat is over propped however. Or dirty hull and stern gear or over weight etc.

 

[hkikis]

Guys the hull and props was absolutely clean before 1 day! Perfect hull! Think that owner at 2200rpm has metered 22knots and today was 23.5 and at 2430 today 28.5 and in his notes was 25! So today was absoloutely cleaned with zero wind! A perfect sea!

The mechanic that I had for the sea trial was official volvo penta of Greece!!!! Yes yes !! And he told me maybe the hull isn't good.. maybe the props or fuel pump/injectors ! But he told me no smokes or anything so for sure props!! Just go to fix the props at prop mechanic and tell him that you want 150rpm more and with 300euro and you will have 2600rpm and you will be perfect!

And now from you I read all this!! Thank you very much for the help because they made me to feel like the crazy buyer with so strange requirements!!! Haha strange requirement to reach volvo rpm!! And I had official volvo mechanic and he told me it is normal..

I know about this golden rule... So that's why I did like crazy !

As I said 28.5 knots max speed but the boat had quite good accelaration! It accelerate quite easy! You can feel that it was powerful! Either volvo mechanic or me, we was sure that engines has good health with compression and good turbos! Because of the acceleration! Ok I after what I read from you I cannot be sure that the problem is the props so thats why I don't feel safe to continue... The seller don't want to fix anything at all!

 

[MapisM]

Didn't you possibly note if whoever was helming lifted the trim tabs before pushing WOT?
And the corresponding fuel burn?
I'm asking because based on your last indications, I would tend to think that it's indeed a matter of shortening props.
I'd look for someone who asks MORE than 300 Eur, though.
Not a job for amateurs with a hammer.

 

[Deleted User YDKXO]

One thing I can tell you is that the boat would not have come out of the Ferretti factory anything other than perfectly set up to pull slightly over 2600rpm at WOT. The boat is not old enough for the engines to have deteriorated sufficiently through wear to give this kind of max rpm drop so something has changed

Has the current or previous owner changed the props in order to achieve faster acceleration at the expense of max rpm/top speed? That seems an unlikely thing to do but its possible

I must say that the fact that the seller refuses to say or do anything further suggests he might know more than he's letting on

 

[MapisM]

Well, he could as well be sure that there's nothing wrong with the boat and that the price is fair.
Mind, I agree that something must have happened in between the moment the boat let the factory and today, but we don't know what.
Surely the props weren't modified to improve acceleration anyway, because that would have made the boat running out of prop, not short of rpm.
The fact that she accelerates well with possibly too long props points exactly in the opposite direction, in fact.
Besides, I don't think any 430 ever reached 30kts even when brand new, and this one was remarkably close, considering that she was 200rpm short.
Lastly, I know it's a larger hull and the 3208 are less powerful, but after all according to the table you posted your F46 only managed 24 kts, and she was also 100rpm short of the rated 2800 of those engines....

 

[hkikis]

If the problem is the the props so with right prop will have better accelaration! But why a previous owner to put wrong props to have worse accelaration and a boat that cannot reach the manufacturer rpm! It doesn't make sense! That's why I am thinking that maybe is something else.

The owner is very experienced person with over 30years with boats and with this boat 10 years and he told me that he didn't know that the boat must reach 2600! This is crazy..

The boat has quite big engines for a 43ft boat. OK it is 17tn but with 960hp engines isn't a under powered boat! Phantom 46 has the same engines! I don't know if 28.5 is good or not but without reach 2600 we don't know if 28.5 is the max! And why to driving this thing with 5th gear in the hill while I must have 4th to be more soft for the engines.

But still I cannot be sure if the props is the problem

 

[hkikis]

Ferretti 430 Review

Here is a review that say that reach 28knot with 420 cat engines!

 

[MapisM]

I don't know if 28.5 is good or not but without reach 2600 we don't know if 28.5 is the max!

Actually, you know it isn't - what you don't know is how much room for improvement there is.
But if the boat reaches 28.5 now, by definition she would be a bit faster, with props shortened just as much as necessary to gain another 200rpm.
By and large, I think it's reasonable to expect 1 additional knots, maybe 1.5. And with an even better acceleration of course.
Besides, I hope you don't mind if I insist, but if by chance the trim tabs were not lifted while running WOT, 1 knot and some rpm would have almost surely be gained just by that.
Not your fault if you didn't check of course, the helmsman should have known.
But if he was the owner, and he never even tried running at WOT in 30 years (which is not as unusual as you might think), well, it's not surprising that he didn't think of it.

Btw, in the article you linked they say that they only reached 27, not 28 kts...
And don't expect that 120hp more are going to turn the boat into a speed demon.
A couple of kts more is all I would expect, if that.

 

[Assassin]

Did they do a static speed test on warmed engines, if it hit the correct figure in neutral, without excess smoke then you know the problem is elsewhere.

If they didn't hit their maximum revs then you know the problem is with the engines.

 

[Bandit]

You say the hull is clean but is it smooth? it makes a difference.

Are the propellers the original ones?

You don't mention engine hours.

These engines will normally over rev before the governors cut in.

I assume the boat is about a 2003? So you will get some deterioration in performance over that time, worn turbos etc.

Not reaching max rpm is not a big deal .

You can have the props re pitched unless they have been re pitched a lot in the past, not a big job but boat has to come out of the water.

If the boat is otherwise in a great condition, the VP engineer has undertaken a thorough inspection of the engines and gearboxes and all OK, and the main survey is good and she is the boat you want It would not put me off.

You can always re-pitch the propellers at the end of the season and then get in to check cutless bearings, engine alignment, stern seals, remove turbos for inspection, clean inlet manifolds etc. Possibly abrasive blast the hull and recoat for a smooth bottom.

 

[vas]

I'd have thought the simplest reason for not reaching WOT would be that at some point owner managed to f#ck the propellers (seen it happen quite a few times with debris or trying stern to in the wrong spot-not deep enough by the dock...) and simply replaced them with something else that thought fit...
Probably what happened with mine which has the opposite problem where it reaches WOT v.quickly but only does 20kn whereas with 660hp for 11tons I'd expect a fair bit more... Old tests of the JLC version with 440hp did 23+kn

 

[Portofino]

Sat in the Sunseeker office in Poole many years ago while waiting for Robert Braithwaite to pop his head round the door and introduce himself , I asked the sales men ....” with it being my first motor boat - is there anything special I should do “
I was coming from sail .
” Always write the numbers of the props down “ they said .

Apparently as Vas infers , they get dinged , it’s more common than you think .....not always the exact same goes back dim wise records are lost @ both ends factory and owners .

Did anyone ...@ the lift ( was it lifted ? ) record the prop numbers ....3 , by any chance ?
pitch
Diameter
serial numbers

Not too sure it’s OCD behaviour as when I went to collect my2nd ever motorboat - ITAMA , the nice Neopolitan broker , while the boat was out at the Apreamare yard did exactly that ...wrote them down inside of the front page of the handbook.
Further more showed me the spare pair fitted under a bunk in the stern cabin , under a bunk bolted down on a dedicated rack .
Tool box with spare nuts and prop spanner’s etc .

I asked him why and pretty much got back a similar answer the Sunseeker guys gave me ....finding the correct props after a ding can be a problem in the Med .
Went on to say depending on the time , they make batches and it can take 3 months , and has known a season ruined by the delays If you have to go down the new route .,,ie the ding can,t be repaired .

Back to the OP s predicament .
Manufacturers seem to make a big deal about correct prop size .
A lot seemingly get dinged .
Availability for replacement can be problematic.
Golden rule is the boat should reach rated rpm @ WOT + a little more eg here near 2700 rpm
Factory sign offs are correctly loaded .

For me I would not be happy with this as in the previous 10 y the owner has had plenty of opportunity to sort out the propping , and despite he VP engineer finding nothing with the engines on the trial , they have been running about basically overloaded since the wrong props are on .So you could be buying future problems .

Find another .

 

[vas]

Find another .

easier said than done in GR Porto...
Not that many boats available, most of them with missing docs/wrong docs/good for export not home use/difficult-impossible to buy as Greek for private use.
And you really DONT wont to embark in a process of buying a 15+yo boat from abroad to bring it in the country...

V.

PS. fwiw, I couldn't for the life of me find any numbers stamped on my props (unless they are on the backside of the boss which is difficult to check with the props in place), PO has died so no idea if they are original and were working fine with the original DD engines with whatever transmission ratio they used back then. For sure they are wrong on my 2:1 twindisk and 2700rpm IVECOs.